glasgow



SAFETY SWITCH Filed e 1924 4 Sheets-Sheet l Ill-Ill 17% v 1 TORNEYI Aug. 27, 1929.

E. M. GLASGOW SAFETY SWITCH Filed Feb. 9, 192

4 Sheets-Sheet 2 III] INVENTOR Er/mff [1. 67a: 0 Mb HZ 1929- E. M. GLASGOW 1,725,789

SAFETY SWITCH Filed Feb. 9, 1924 4 sheeisrsneet 3 INVENTOR Fri??? dlasgvn ATTORNEY! Patented Aug. 27, 1929.

UNITED STATES 4 1,725,789 PATEN orr c.

ERNEST M. GLASGOW, 0F PORT CHESTER, NEW YORK, ASSIGNOR TO RUSSELL & STOEL COMPANY, OF NEYV YORK, N. Y., 'A CORPORATION OF NEW YORK.

SAFETY SWITCH.

Application filed February 9, 1924. Serial No. 691,606.

My invention relates to the construction of electric switches of the type wherein the switch itself has a snap action and wherein fuses within tlie enclosure.

provision is also made for the substitution of' to expose the switch-mechanism while the switch is closed and the switch must be thrown to otf position to'permit the cover tobe. removed while conversely it: is necessary to fully restore the c over before the switch can function to close the circuit. 1 l

The object of the invention is also to provide an improved construction such that thehandle "must be r manipulated ina direction to open the switch before the cover can be removed and also beforeit can be restored, the restoration then freeing the switch tozpermit it to be moved back to closed positionfi The special objectiof this part of the invention'is to insure the'opening of the switch before the box is'opened thereby makingthe device immune from da'nger inuse under all conditions'or iii-the case through derangement by unwarrantable interference or through accident, the-parts within the box should be in a conditionwhich would permit the cover to be removed while the circuit is closed -r A further object of the invention .is to insure a condition of safetyat the fuse-clips before or while the cover is removed so that fuses may be removed or replaced without any danger whatever by reason'of-the fact that the fuse clips themselves are disconnected both'froni the line and from the circuit which is made dead by throwing the'main.

the casing, the insulating plate supportingthe fuse clips being removed and parts being shown in section on the line 11 Fig. 2.

Fig. 2 is a side elevation of the mechanism, the box and supporting plate of insulating material within the same being shown in vertical longitudinal section.

Fig. 3 is an end-elevation-of the apparatus within the box, said boxbeing shown in vertical cross-section. u

Fig. 4 is a plan of the .plate of insulating -material supportingthe fuse clips, thesW-itch contacts and switch blades supported on-the under side of said plate being indicated'in .dotted lines.

f Fig. 5 is avertical section on the line I '1 Fig. 6 is an-elevationof the box vin-reduced ;size as ordinarily mounted for use. 1

1 indicatesthe switch box, 2 the cover-piv- ,;oted for instance at- 3 on one side and;held .down by a clamp nut Jr-at. the other'side (see Figs. 1 and 2). The operating shaft shown at 5 is provided with a handle 6'and may be turned by the latter in eitherdir'ection, to

.throw the switch from on to oif or vice ve'rsa. Said shaft is mountedto becapable of turning in suitable bearings consisting for instance of bosses 5 projecting from the inner face of the wall of the casing. Between said bearings 5 the shaft ismounted and turns in a pair of b rackets'5 Whichdepend from'a plate or frame 9 secured to the lower face of an insulatin slate or-other; base 9. Said base 9 is suitably supported byfilugs or other means within the casing at a point below and sufficiently removed from the top edge thereof to afford space for the fuse and fuse clips supported directly thereon and carries on its inner face all of the switch contacts of the snap switch together with the switch blades or similar members co-opcrating therewith and likewise the snap switch mechanism to be presently describe The switch arm or arms supporting the blades of the switch consist preferably of a pair of arms 11 suitably fulcrumed. to be capable of turning independently of the handle-actuatedshaft'5. In the present instance said' arms are, for compactness and simplicity of structure, fulcrumed on the shaft 5 itself between the brackets 5 and sand arms are connected by a cross member or rod 11 to insure the rigidity of the switch arm thus constructed.

The switch blades of any desired number, are indicated at 7. These switch blades operate in pairs, (one pair for each pole of the circuit) to make and break a connection between one side of the main line and the corresponding side of a local or serw'ee line and each member of a pair is moved into and out with pairs of which each one of a pair of blades co-opera te to open and close the circuit by bridging or opening abridge between a pairof contacts at both ends of the bridge are indicated at 8 and each contact comprises preferably a pair of springs which project from a block of metal properly secured to the under side of the insulating plate 9 so the pairs-ofsprings will project inwardly from said base. 'The switch blades -7 enter in the usual manner between the pairs of springs 8 to close the circuit by bridging the members of a pair of springs. These members 8 and 7 a t after the manner of the knife blades and spring contacts of the ordinary knife switch;

Pairs of-springs 8 one pair for each pole of the circuit are mounted upon and project outwardly from the base 9 and constitute clips for the fuses 8'. These clips 8' are suitably connected with the bases of the double confacts 8, as will be presently described, and in such manner that when the switch is operated to dis-connect the service or local line from the main line, both fuse terminals will be also disconnected from said lines so that the fuses may be then removed and a new fuse substituted without danger of shock from leakage back from the local or service line in case the servite line may have become cro$ed with some other line or circuit and also with the obvious effect of protection from shock from the main line.

Also, as will be seen, all of the switch terminals are effectii'ely shielded from accidental contact by reason of the fact that they project from the under side only of the insulating plate 9 and are not in any manner exposed when the cover 2 of the box is removed for the purpose of substituting a fuse.

From the shaft 5 projects an arm 12 keyed to the shaft 5 and pivotally connected to or linked up with a link 13 the ivota-l connection or pivot pin being exten ed laterally as indicated at 13'. (See Fig. 1). The link 13 terminates in or carries a cross pin 14 which engages slots 15 in the switch arms 11. These slots 15 are elongated in a direction to permit limited lost motion of the link 13 and operat ing shaft 5 when the latter is turned by the operating handle. The pin 14 is coupled to the switch arm by engagement with the sides of the slot and acts as a dog to hold the switch arm 11 from movement under the influenoe of the snap action spring while the spring is being put under tension as will he presently described, said dog for this purpose co-operating with a suitable stop from which it is disengaged .under the action of the turning movement of the shaft 5 in winding up the snap action spring.

The stop device consists of a pair of stop latches 19, 19 one of which holds the dog and switch arms 11 temporarily when the shaft 12 is turned to open the switch, while the otheracts-on the reverse moven'ient whereby the switch is closed. The snap action spring is indicated at 16 and is wound around the main operating shaft 5. Said spring is normally without tension but movement of the shaftin either direction places it under tension. The free extremities of the spring are operatively connected respectively with the switch arms 11 in any desired way to act respectively :on the same in opposite directions. Thus, for instance, one free end there.- of may hookon top of one of the pairs of switch arms 11 to move them in one direction while the other free end hooks underneath one of said arms and is thereby operati\ol connected with the compound switch arm to actuate said arm in the opposite direction.

The winding up action of the spring is socured by engagement of the ends of the pin 13 therewith. One end of said pin engages the spring on its upper side and the other engages it on its under side. As will be obvious. the turning of the arm 12 secured to the shaft in a downward direction, for instance. will wind up one end of the spring, by engagement of one end of pin 13 with the top side of the spring, while the other end of the spring being hooked on top of the switch arm will upply the snap spring action to the arm 11when the arm is released by disengagement of lliu dog from the stop or catch with which it is engaged until withdrawn from cugagcn'ienl by the movement thereof in the slot inward toward the shaft 5 by the action of the link 1 The other end of pin 13 engaging under the opposite end of the spring will, on turning of the shaft in the opposite direction, wind up said end while the opposite end which books under the arm will throw it in the opposite direction when the arm is released by disengagement of the pin or dog 14 from the latch or stop which normally opposes the. movement until, in the winding up movement of the shaft, said dog has been drawn inward toward the shaft away from engagement with said stop or latch. The stop or latch devices: engaged by the dog 1 1 are two in number and are preferably constructed and mounted. as follows:-

A fixed support for the same comp-rises preferably the fixed bracket or yoke 1? which may be cast in one piece with or properly cured to the supporting plate 9 and projects inwardly from the insulating plate: 9, as

shown. These latches or stops consist of a Hill pair of shouldered plates 19, 19, the former of which is pivotally supported between the arms of the yoke or bracket 17 near the lower end thereof, while the other plate 19 is mounted on a pivot or pivotal support exten ding between the arms of the bracket near the upper end thereof, as shown clearly in Figs.

2 and 3. The plates 19, 19 are adapted to swing freely and independently of one another in said fixed bracket or yoke 17 and are connected to one another by a spring 18 which normally tends to project the latches into position so that the dog 14 will engage and be locked by one or the other of them as shown in the case of latch 19. One of said latches, to

wit, the latch 19, locks the dog 14 while the spring is being wound up preparatory to a throwing of the switch to open position, while the other latch or stop 19' similarly locks the dog and switch arm during the winding up action of the spring by the shaft 5 preparatory to the movement of the switch to closed position. A pin 20 supported in the yoke 17 passes transversely through an opening in the latches 19, 19' and serves as a stop pin to limit their motion under the action of the spring 18.

When the dog is disengaged from the shoulder 0f the latch or stop by which itis locked,

it passes freely over the inclined side of the other latch until it reaches position to permit the latch to spring out so that the shoulder thereof will pass over the dog 14 and the lat ter will be thereafter locked by said latch until the dog is again withdrawn from locking 30 position.

The drawing Fig. 2 shows the switch in closed position. The turning of the shaft handle 6 to throw the switch arm to off position winds up the snap action spring 16 and finally Withdraws the dog 14 from locking position on the shoulder of latch 19. Thereupon the switch arm is thrown by the action of the spring which is being placed under tension while winding up one end thereof.

The switch now assumes the off position indicated in dotted lines and the dog 14 is locked under the shoulder of the other latch. A reverse movement of the shaft 5 by the handle 6 to close the switch now winds up the oppos te end of the spring until. during the winding movement, the dog has been pulled in toward the shaft 5 sufficiently to be disengaged from the shoulder of the second latch 19 whereupon the spring, by engaging under the switch arm by its opposite hooked end, throws the arm back to the closed position.

The interlocking of the cover and the switch is accomplished by the following dcvices. 21 is a pivoted catch pivotally mounted G0 on and depending from the casting or plate 9' secured to the insulating plate 9. A spring 21' tends to move it in the direction of the arrow (see Fig. 2). The cross-bar or member 11 of the switch arm moves in the vertical,

slightly curved slotin the catch 21 and is adapted to engage with a shoulder 23 of said catch when the switch arm is in the open position and the catch 21 has been moved over by the spring 21' into the position indicated in dotted lines. In this position of the parts the switch is locked in open or off position. The catch 21 is normally retained, however, ininoperative relation to the switch arm by a lug 25 carried by the cover and engaging the catch 21 to hold it over in the position indicated in full lines while the cover is in closed position, thereby permitting the switch to be operated as a snap switch in the usual way so long as the cover is down. The lug 25 extends downwardly from the cover to an opening in plate 9 and then engages, by means of an insulating projection 26, with an upwardly ex tending projection 27 carried by the pivoted catch 21 and extending into the opening in the plate 9 as clearly shown. When the cover is thrown up, after throwing the switch to open position, the catch 21 is released and assumes position for locking the switch in open or off position.

The cover cannot be moved to expose the fuses or the interior mechanism of the box until after the switch has been thrown to off position or position indicated in dotted lines. The means for securing this result consist of a hook or catch 28 extending from the arm 12 of the operating shaft 5 and interlocking with a bar 29 extending downwardly from the cover and having an opening at its lower end through which the hook passes. Only when the switch is thrown down to off position and slightly beyond can the hook 28 be moved sufliciently to release the bar 29 and thus permit the cover to be raised. This re sult is attained by making the hook 28 so long that even after the switch has been thrown to the position indicated in dotted lines in Fig. 2, the end of the hook will not be fully withdrawn from the aligning opening in the locking bar 29. That is to say, if the switch be snapped to ofi position by operating the handle 6, the cover 2 will be still locked down unless a further movement is given to the operating handle and shaft, resulting in turning the hook 28 sufiiciently to withdraw its end fully from the opening in the bar 29. This movement is given simply by pressing the handle in the general direction of the 0H movement to position beyond the position in which the handle is left for off position of the switch. This further movement is permitted without obstruction from the switch arm which at such time is in off position because the arm 12 and connected parts, being capable of lost motion with respect to the switch arm as already described, may make the further required movement for effecting full release between 28 and 29 without interference from the position of the switch arm which has completed its action under the snapping effect of the spring 16.

When the handle 6 is pressed in the direction described as off the box may be opened by lifting the cover. This insures a manipulation of the switch to off position before the box can be opened. Obviously when the pressure is removed and the box cover is up the hook 28 will return a slight distance toward normal position but will then be in position to be engaged by the end of the bar 29. This will prevent the cover from being thrown down fully should the attempt be made to close the box without throwing the switch to ofi position, and also results in holding the cover up sufiiciently to prevent the cover from releasing the catch 21 which it must do in order that the switch may be snapped back to closed position. Hence, when the box is open it is likewise necessary to throw the handle 6 to full off position or in a direction to open the switch before the cover can be thrown down to fully closed position which is the position it must reach before it will unlock the switch arm from the restraint of the catch 21.

Secured in the bottom of the box 1 is a slate or other insulating base 30 on which are mounted conecting blocks 31, 31, for attachment of the main line or service or local cables. From these blocks extend the interior cables 32, 32' whose free ends beneath the slate base 9 are fastened to the conducting blocks which carry respectively the various line and service contacts 8 of the knife switch. said blocks being attached to the under side of the slate base 9 and having the spring contacts 8 projecting therefrom do \vnwardly away from the base. One of the two openings in the end of the boX through which the main line and local cables may be introduced for attachment to the connecting blocks 31, 31 is indicated at 33. For convenience of attachment, the connecting cables 32 within the box are used as the main line connecting cables and the cables 32 as connecting cables from the local or service line, although a reverse arrangement might be employed using the connections 32 as the local or service line connections. Assuming that the latter are used as the main line connections and the cables 32 as the service line connections, the connection to the various switch contacts may be made by attachment of the cable ends to the blocks carrying said switch contacts in the order or arrangement indicated in Fig. 4 where the various switch contacts and blades beneath the slate base 9 are indicated in dotted lines. Two fuse clips 8' at one end of the slate base and rising therefrom are located opposite one of the two contacts 8 at the same end of the base and are in immediate connection therewith through the screws or bolts 34 which fasten the base blocks for said contacts and clips to the opposite face respectively of the slate base 9. At the other end of the slate base 9 fuse clips 8 are fastened directly to the upper face of the base by the screws 34. Connection is established between them and the contacts 8 with which the blades 7 cooperate to close the connection from the main line terminal switch contacts 8, by means of straps 35 fastened by means of the screws 34 under the block from which the fuse clip rises, and at the other end fastened down upon the upper face of the block by screws 36 which extends through the base and fastens the local or service line switch contact 8 to the under surface of the slate base.

As will be seen .b 1 reference particularly to Fig. 4, two pairs of blades are employed, one pair for each pole of the circuit, and each member of a pair is moved bodily by the action of the arm 11 into and out of bridging relation with a pair of contacts 8 one member of one of said pairsof contacts being connected beneath the insulating plate or base 9 with a local or service connecting wire or cable 32' while the other member of said pair of contacts is directly joined by means of a screw or bolt 34 with one of the pair of fuse clips 8 used for the corresponding pole of the circuit. The other member 7 of the pair of blades now referred to is correspondingly and at the same time brought into and out ofbridging relation with another pair of contacts 8 one joined beneath the plate or base 9 with the main line connecting wire or cable 32 while the other one of the pair of contacts with which said plate cooperates is suitably joined with the base of the other member 8' of the pair of fuse clips referred to.

The connection thus established through the switch contacts, the blades, fuse clips and the fuses may be readily traced by the arrows and the result of the arrangement is that when the blades of a pair sever connection each with its pair of contacts 8, not only is the connection between the main line and the local or service line interrupted at two points but the fuse clips 8' are disconnected from both the main line and the service or local line thereby permitting the fuses to be substituted without danger. Moreover, inasmuch all the main line and service line contacts of the switch and the connections thereto are arranged on the under side of the base 9 and project downwardly therefrom there is no possibility of contact therewith by the hand of the operator.

The particular construction of snap switch or snap switch action hereinbefore described forms the subject of claims in my application filed Oct. 23, 1924, as a division hereof, Serial No. 745,270.

lVhat I claim as my invention is 1- 1. In a safety switch, the combination of an operating shaft, a switch arm, a hook carried by and movable with said shaft, a cover, a locking bar fixedly mounted on said cover and engaged by said hook and a snap action dog connected with the arm by a lost motion whereby further movement in the direction for opening the switch may be imparted to thehook after the switch arm has come to rest in the off position to thereby move the hook out of engagement with said locking bar.

2. In a safety switch, the combination of a switch arm, an operating shaft operatively connected with the arm for throwing the same to off position, said shaft having a lost motion with respect to the arm and interlocking means between the shaft and cover comprising a member carried by and moving with said operating shaft and a cooperating member fixed in position on the cover, said members interlocking directly with one another in the normal off position of the operating shaft and being adapted to be disengaged by moving the operating shaft beyond its normal off position.

3. In a safety switch, a switch operating member, a casing, a cover for said casing, latching means for maintaining said cover latched in its closed position in both the closed and open positions of said switch, yieldable means permitting the movement of said switch operating member to a point beyond the normal open condition of said switch for releasing said cover from said latching means.

4. In a safety switch, the combination of an operating shaft, a switch arm, latching means movable with said switch arm, a cover, cooperating latching means movable with said cover, movable switch blades, connecting means pivotally connected to said shaft and movably mounted on said switch blades, cooperating locking dogs for securing said switch blades from movement in the opposite direction from either open or closed position, said switch blades being released from said locking dogs by the movement of said connecting means relatively to said switch blades.

Signed at New York, in the county of New York and State of New York, this 8th day of February A. D. 1924.

ERNEST M. GLASGOW. 

